Enhancing the gas selectivity of single-crystal SnO2:Pt thin-film chemiresistor microarray by SiO2 membrane coating

We consider application of SiO2 coating as a coverage membrane to differentiate local gas-sensing properties of tin dioxide thin film employed in gas-analytical single-crystal multisensor microarrays. The approach is tested utilizing homogeneous and non-homogeneous coatings. It is found out that the SiO2 coating of homogeneous thickness, of 7 nm, just reduces gas response and gas recognition ability of the microarrays which might be explained by appearance of additional defects in the SnO2 film under Ar+ bombardment assisting the SiO2 deposition. The deposition of SiO2 coating of non-homogeneous thickness, of 2-24 nm, results in substantial enhancing of gas selectivity of the developed microarrays